[fitsbits] start of Public Comment Period on the column limits convention

[Tom McGlynn (NASA/GSFC Code 660.1)]

One question that I'd like to see clarified for these keyword is whether 
if a have
   TDMINx and TDMAXx
that there is required to be an actual row I can point to which has this 
value?

Do we need to worry about round off errors between the binary and text 
representation of numbers?
E.g., suppose a number x is the minimum value in a table and
    d.dddddddddddd
is way that, e..g, Java, renders this value at full precision.
I write
     TDMINx = d.ddddddddd
Have we violated the FITS standard if in infinite precision arithmetic 
d.ddddddddd is actually > x.

Alternatively do I have an error if I decide to address this issue but 
subtracting a small delta from the minimum
such that my actual the value I have in the TDMINx is a teeny bit less 
than x.

Not sure of how we address this precision issue but I think the language 
currently is to restrictive.

     Tom McGlynn


Lucio Chiappetti wrote:
> ANNOUNCEMENT:  START OF FORMAL PUBLIC COMMENT PERIOD
>
> This is to announce the official start of a 3-week formal Public Comment
> Period on the incorporation of colum limit (aka TLMIN TLMAX) convention in
> the FITS Standard.
>
> This is part of a process to incorporate the most useful, widely used
> registered, and simple conventions (which are valid FITS constructs) into
> the official definition of the standard.
>
> This convention defines the TLMINn/TLMAXn and TDMINn/TDMAXn keywords
> describing the minimum and maximum values in table columns
>
> The proposed text consists just
>
> - in the ADDITION of a new section 4.4.2.7 (hilighted in violet colour)
>    describing the four keywords
>
> - in the addition of CROSS REFERENCES to it in 7.2.2 and 7.3.2 (resp.
>    for ASCII and binary tables)
>
>     and has been prepared by a technical team including L.Chiappetti,
>     W.Pence, A.Dobrzycki, R.A.Shaw and W.Thompson (main editor
>     W.Pence).
>
> - If the proposal is approved a section H.3 will be added to Appendix H
>    describing the update, and the keywords will be listed in Appendix C
>
> The proposed draft text is available at
> http://sax.iasf-milano.inaf.it/~lucio/FITS/Conventions/minmax-upd2.pdf
>
> Supporting material is provided in the FITS Convention Registry at the
> following URL http://fits.gsfc.nasa.gov/registry/colminmax.html
>
> For general considerations on the Public Comment Period, the IAUFEC review
> and background information on the FITS approval process please refer to
> the announcement of Public Comment Period for CONTINUE issued earilier
> today.
>
> Please review the text carefully and post any comments, criticisms, or
> suggestions on the FITSBITS mailing list, separately for each convention.
> ==================================================================
>
> The Public Comment Period starts today 19 June 2015 and will last formally
> for 3 weeks until July 9 included.
>